The DVD includes copies of the Gentoo installation handbooks for x86, amd64 and ppc. It is important to use the correct handbook for your architecture. this point is made in the installation instructions i the magazine.

"Insanity: doing the same thing over and over again and expecting different results." (Albert Einstein)

If you burn the amd64 iso from the DVD, it's the manual on the disc you've burned that's short.
The one on the DVD is okay, but the boot disc version misses out the bootstrapping section of chapter six.
I was half-expecting some fancy new build-kernel-then-bootstrap affair, but then "emerge gentoo-sources" crashed out pretty quickly. Not a problem if you're used to gentoo, bit cruel on noobs though...